There's a deeply ingrained mythos around how natural and easy motherhood is, but in nature, a lot of first time mothers are rather mediocre. It takes a while learn how to do all those "natural" things like nursing the baby.
And let's not forget that babies kinda suck (intended) at doing "natural" things too.
It used to be that people had between six and twelve children, so all children grew up among babies learning this crucial knowledge from their parents and younger siblings. They'd end up having children within a few years of moving out, too, so there was no forgetting about it, either.
In addition, a lot of first time mothers died, as did their babies.
> lot of first time mothers are rather mediocre
I had a hen who was sitting on a clutch of eggs this summer. Did everything right: kept them warm, turned them regularly, etc.
Then one hatched and she promptly lost interest in the rest, leaving them to die.